The Tamil Nadu Police has dropped a case against Chief Minister M Karunanidhi and his son and the then city mayor M K Stalin, filed by the previous AIADMK regime in connection with alleged irregularities in the construction of some flyovers in the city, allegedly causing the Chennai Corporation a loss of Rs 12 crore.

The police said they have dropped the 'mini flyover case' due to "insufficient evidence to pursue the case," which is technically specified as "mistake of facts."

Karunanidhi was arrested at midnight in June 2001, provoking statewide protests, while Stalin had surrendered before the Principal Sessions Judge the next morning.

Though the police had filed an FIR in 2001, a chargesheet is yet to be filed.

Besides Karunanidhi and Stalin, others named in the FIR include DMK ministers K Ponmudi and Ko Si Mani, and former Chief Secretary KA Nambiar.

In May 2006, after the DMK was voted to power, the CB-CID had sought permission from a sessions court to investigate further into the case. However, since no evidence was found, it was subsequently dropped.

According to the CB-CID, the accused were guilty of offences under IPC sections 120-B (criminal conspiracy), 420 (cheating) and section 13(1) (d) and (c) of the Prevention of Corruption Act.

Earlier, a chargesheet, which was presented to the judge, was not taken cognisance of, by the court.